https://www.reddit.com/r/interestingasfuck/comments/76g6vt/how_vending_machines_identify_fake_coins/
origin - http://www.pipiscrew.com/2017/10/how-vending-machines-identify-fake-coins/ how-vending-machines-identify-fake-coins
https://www.reddit.com/r/interestingasfuck/comments/76g6vt/how_vending_machines_identify_fake_coins/
origin - http://www.pipiscrew.com/2017/10/how-vending-machines-identify-fake-coins/ how-vending-machines-identify-fake-coins